I wrote:
> clang in C++ mode accepts the compound initializer syntax
> (TYPE) { VALUE... }
> but — unlike gcc in C++ mode — requires that the values be constant
> expressions.
But that is not universally true. It depends on the context.
In any case, static_cast<TYPE> works fine regardless of C++ version
and C++ compiler.
Test program below.
Bruno
================================ foo.cc ================================
/* Compile this with g++ or clang++ >= 4. */
extern int foo;
extern int bar ();
struct s { int x; };
/* In normal expression context: */
int f1 (void) {
return (int){ foo } + (int){ bar () };
}
#if __cplusplus >= 201100
int f2 (void) {
return int{ foo } + int{ bar () };
}
#endif
struct s f3 (void) {
return (struct s){ foo };
};
struct s f4 (void) {
return (struct s){ bar () };
};
struct s f5 (void) {
return (struct s){ .x = foo };
};
struct s f6 (void) {
return (struct s){ .x = bar () };
};
#if __cplusplus >= 201100
struct s f7 (void) {
return s{ foo };
};
struct s f8 (void) {
return s{ bar () };
};
#endif
int f9 (void) {
return static_cast<int> (foo) + static_cast<int> (bar ());
}
/* In initializer context: */
#if !defined __clang__ /* error: initializer element is not a compile-time
constant */
int v1 = (int){ foo } + (int){ bar () };
#if __cplusplus >= 201100
int v2 = int{ foo } + int{ bar () };
#endif
struct s v3 = (struct s){ foo };
struct s v4 = (struct s){ bar () };
struct s v5 = (struct s){ .x = foo };
struct s v6 = (struct s){ .x = bar () };
#endif
#if __cplusplus >= 201100
struct s v7 = s{ foo };
struct s v8 = s{ bar () };
#endif
int v9 = static_cast<int> (foo) + static_cast<int> (bar ());
